This invention relates to a combined rotary vane engine, particularly to a rotary engine with a single vane and a biased rotor.
In the prior art, three typical structures of rotary engine are: a rotary engine with vane(s), a rotary engine with engagement of toothed gears or the like, and a rotary engine with oscillating motion. Additionally, the rotary engine with vane(s) has many variations, one of which is a rotary vane engine with an eccentric rotor, to which this invention is directed.
The main structural features of such an engine are as follows: the cylinder is of cylindrical shape; a shaft is provided at the axis passing the center of the cylinder; a vane rotating around the axis is disposed radially between the axis and the internal wall of the cylinder; a hollow cylindrical rotor with a longitudinal slot is located eccentrically in the cylinder around said center shaft, and the external wall of the rotor is tangential to the internal wall of the cylinder; a combustion chamber, the volume of which changes with the rotation of the vane, is formed between the external wall of the rotor and the internal wall of the cylinder so as to execute the working cycle of the internal combustion engine. Such an engine may have a vane or a plurality of vanes, as disclosed in, e.g., U.S. Pat. Nos. 3,132,632, 2,969,049 and 3,289,653.
Up to now the rotary engine is not widely used in practice because it has serious deficiencies and cannot realize the requirement for simple, reliable and highly efficient work. The references mentioned above are taken into account, for example: for such an engine with a plurality of vanes as in U.S. Pat. No. 3,132,632, the angles between said vanes are varied during operation, so that these vanes cannot be all fixed on the center shaft. Therefore, power output is realized by function of the vanes which move the eccentric rotor. Under the mutual action between the great pressure, which is produced during explosion of the combustion gas, and the load, a great stress may be caused between the vanes and the slot from which the vane projects, thus causing the slide or sealing member to quickly wear out. As a result, the whole engine fails.
For such an engine with a single vane, as disclosed in U.S. Pat. Nos. 2,969,049 and 3,289,653, although the power output mode in which the vane is fixed with the center shaft is used, there exist some obvious deficiencies. First, it is necessary for the engine of U.S. Pat. No. 2,969,049 to provide a set of special mechanisms to drive the .eccentric rotor and the vane to execute the working cycle. Therefore, the eccentric rotor rotates on the internal wall of the cylinder by the action of the drive means, thus the structure is complicated, and it is difficult to achieve the seal and lubrication. Moreover, during operation, a great stress may be produced between the vane and the rotor, thus causing the sealing member to wear out, causing the whole engine to fail.
Additionally, both of the above-mentioned technical solutions have another similar deficiency. That is, since the working space of the engine is crescent and limited, it is difficult for the energy of the combustion gas by the explosion stroke to be used efficiently while rotating at a high speed (the explosion angle of rotation being less than 180.degree. of the rotation angle of the vanes), and the compression stroke is equal to the explosion stroke, which leaves surplus energy to be discharged, thus wasting energy and lowering efficiency.
Moreover, there exist the following deficiencies in the technical solution of U.S. Pat. No. 3,289,653:
1. The structure is unreasonable. Since the working mode in which the internal cylinder is for suction and compression, and the external cylinder is for combustion and action, it is difficult to realize an optimum ratio of working volumes;
2. A high sealing requirement is needed between the front and the back of the vanes, both ends of the rotor and the external wall, vane and rotor, so that the sealing is complicated and difficult, and reliability is worse;
3. Since both internal and external cylinders are all working chambers, effective lubrication and cooling is not provided between the chambers or in the chamber;
4. Because a very long compression gas pipe is provided between the compression cylinder and the working cylinder, the exhaust gas produced in combustion cannot be fully discharged out in the discharge stroke, thus lowering the combustion efficiency;
5. Gas passage is opened and closed by a disk turning valve, the structure is complicated and reliability is worse.